The present invention relates to a valve-timing control apparatus for an internal combustion engine, in which opening and closing timings of an intake valve and/or an exhaust valve are controlled.
Japanese Patent Application Publication No. 2012-132367 discloses a previously-proposed valve-timing control apparatus for an internal combustion engine.
In this technique, a cover member is provided on a front end side of a motor housing for an electric motor. A retaining member that slidably retains a pair of power-feeding brushes is attached to the cover member. Each of the pair of power-feeding brushes includes a backend portion which is connected through a pigtail harness to a connector terminal of a power-source connector, and a tip portion which is elastically in contact with a slip ring by biasing force of a coil spring to be slidable on the slip ring.
Electric current supplied through the pigtail harness and the power-source connector from a battery is applied through the power-feeding brush, the slip ring, a switching brush and a commutator to a coil of the electric motor. Accordingly, an output shaft of the electric motor is drivingly rotated.
Rotational driving force of the electric motor is transmitted through a speed-reduction mechanism to a cam shaft so that a relative rotational phase between the cam shaft and a timing sprocket is changed. Thus, the opening and closing timings of the intake valve and/or exhaust valve are controlled.